Coronado ADU Laws (2026): What’s Allowed, What State Law Overrides, and Real Permit Timelines

Last updated: May 14, 2026 · Last verified against primary sources: May 14, 2026

Coronado ADU laws in 2026 let most residential lots add an accessory dwelling unit, but the legal path depends on whether your project is a local-code ADU, a state-protected detached ADU, a conversion ADU, a junior ADU (JADU), a carriage-house conversion, or a multifamily ADU. The city caps detached ADUs at 850 square feet (studio or one-bedroom) or 1,000 square feet (two or more bedrooms), with four-foot side and rear setbacks and a 16-foot detached height limit. California state law overrides several of these. ADUs on lots within ½-mile walking distance of the Coronado Ferry Terminal are entitled to 18-foot heights — plus up to two additional feet when needed to align the ADU roof pitch with the primary dwelling’s roof pitch. The City must decide a complete application within 60 days, though our review of public Coronado permit records from January 2025 through April 2026 shows real-world spans from same-day issuance to 412 calendar days. Identify your legal path before you pay for plans.

What are the Coronado ADU laws at a glance in 2026?

We assembled this snapshot from Coronado Municipal Code §86.56.105, the California Government Code, and the December 10, 2025 HCD findings letter on Coronado’s ordinance. Sources are linked under each section.

Can you build an ADU on a Coronado property?

A Coronado property is a candidate for an ADU if it sits in a residential or mixed-use zone and has — or will have — a primary dwelling. The next question is rarely “is it allowed?” It is “which ADU path fits this lot?” Coronado’s ordinance recognizes six distinct paths.

Single-family lots: one ADU or one JADU, plus state-law combinations

Coronado’s local ordinance, at CMC §86.56.105.B.5, says no more than one JADU or one ADU per single-family lot, “except as permitted in subsection (C)(2)” — language the city added in 2024 to acknowledge California’s Government Code §66323 protected combinations. Read together with state law, most single-family lots in Coronado have these viable paths:

1. One ADU under local development standards (the 850/1,000-sq-ft path), or
2. One detached ADU up to 800 sq ft, 16 ft tall, with four-foot side/rear setbacks under §66323(a)(2), plus a JADU on the same lot when site conditions allow.

State law (§66323) also supports a conversion ADU plus a JADU, and in some cases a §66323-protected detached ADU plus a conversion ADU plus a JADU when site conditions and unit criteria are met.

Multifamily lots: the state-law expansion to eight detached ADUs

Coronado’s local text has historically referenced “up to two detached ADUs” on multifamily lots. State law has gone much further. Under §66323(a)(4), a lot with an existing multifamily dwelling is entitled to up to eight detached ADUs, capped at the number of existing units on the lot. A four-unit existing building can add four detached ADUs; an eight-unit building can add eight. Owners may also convert non-livable space into ADUs up to 25 percent of the existing unit count, with a minimum of one conversion ADU regardless.

HCD’s December 10, 2025 letter flagged Coronado’s “two detached ADUs” language as non-compliant with state law (Finding 25). We treat the eight-ADU formula as the controlling rule until the city’s ordinance amendment is on record.

New primary dwelling + ADU at the same time

Under Government Code §66317, an owner may submit ADU and primary-dwelling applications concurrently. The city may delay approving or denying the ADU until it acts on the primary dwelling, but it cannot refuse to accept the application. Bring §66317 to your pre-application meeting if you intend to build a primary home and ADU together.

Coronado Cays, Coronado Shores, and properties with HOAs

City approval and private CC&R or HOA compliance are separate questions. Under California’s AB 670 (2019), an HOA cannot outright prohibit an ADU on a single-family lot. AB 130 (Statutes of 2025) further clarifies that HOAs may not impose fees or financial requirements tied to ADU development. HOAs can impose reasonable, objective design and aesthetic standards.

The Coronado Cays HOA member handbook contains specific ADU restrictions worth knowing before you design: the handbook documents that ADUs and JADUs (and garage conversions) are prohibited in the Cays’ condominium villages, and that City-permitted ADUs/JADUs require prior written Association approval in other villages. Treat this as a private-restriction issue to verify against the current handbook, your specific village, and counsel.

Where does California state law override Coronado’s ADU ordinance?

Answer capsule: On December 10, 2025, the California Department of Housing and Community Development (HCD) issued written findings that Coronado’s ADU ordinance (No. 2024-02, adopted April 16, 2024) fails to comply with state law on 31 separate points. Government Code §66326 gave the city up to 30 days to respond. Until Coronado either amends the ordinance to comply or adopts findings explaining why it complies despite HCD’s view, the practical reading for homeowners is that state law controls on the 31 flagged points.

This single document is the most important read for any Coronado homeowner considering an ADU in 2026. We pulled the full findings letter and decoded each finding below into homeowner-level impact.

The 31 HCD findings, decoded

The table below condenses HCD’s letter into the practical question every homeowner should ask: does this Coronado rule actually bind me? We paraphrase each finding rather than quoting at length.

Source for all rows below: HCD letter to Richard Grunow, Director of Community Development, dated December 10, 2025.

Coronado ADU size and height limits compared to California state law.

How big and tall can a Coronado ADU be?

Answer capsule: Coronado caps ADUs at 850 square feet for studio or one-bedroom units and 1,000 square feet for units with two or more bedrooms. Detached ADU height is locally capped at 16 feet, but state law requires the city to allow 18 feet, plus up to two additional feet to align the ADU roof pitch with the primary dwelling’s roof pitch, for any ADU on a lot within ½-mile walking distance of a major transit stop. The Coronado Ferry Terminal is the major transit stop in this analysis. Walking distance — not radius — is the legal standard.

The local size caps: 850 / 1,000 / 500

Coronado’s plain rule under CMC §86.56.105.B.7:

• Studio or one-bedroom ADU: up to 850 sq ft of floor area.
• Two-or-more-bedroom ADU: up to 1,000 sq ft of floor area.
• JADU: up to 500 sq ft (now defined as “interior livable space” under SB 543).

These caps are enforceable on a single-family detached ADU built under the city’s standard development standards. They are not enforceable on three of the four §66323 ADU types:

1. §66323(a)(1) single-family conversion ADUs
2. §66323(a)(3) multifamily conversion ADUs
3. §66323(a)(4) ADUs detached from a multifamily dwelling

The 800-sq-ft state-protected baseline

Under Government Code §66321(b)(3), Coronado must permit at least an 800-sq-ft attached or detached ADU on any qualifying single-family lot, with four-foot side and rear setbacks, even if the city’s other development standards (lot coverage, floor area ratio, open space, front setbacks) would otherwise preclude it. The 800-sq-ft baseline is your fallback when standard zoning would otherwise block construction.

Detached height: the Coronado Ferry Terminal walking-distance bonus

The local rule (CMC §86.56.105.B.3.c) caps detached ADU height at 16 feet. Government Code §66321(b)(4) requires the city to allow:

• 16 feet as the floor on lots without transit adjacency.
• 18 feet on lots within ½-mile walking distance of a major transit stop or high-quality transit corridor — and up to two additional feet (so 20 feet total) only when needed to align the ADU roof pitch with an existing single-family primary dwelling’s roof pitch. The extra two feet is conditional on roof-pitch alignment, not automatic.
• 25 feet for attached ADUs that match the primary dwelling’s height limit, subject to other state-law conditions.

The statute is clear that the measurement is walking distance, not a straight-line radius. HCD’s findings letter, in footnote 36, names the Coronado Ferry Terminal at 1201 First Street as a qualifying major transit stop under Public Resources Code §21155(b).

Roof decks, balconies, and design review

A practical Coronado wrinkle most generic ADU pages miss: the city has explicit roof-deck and balcony standards in its zoning code. Walking surfaces 14 feet or higher on residential property typically require Design Review Commission approval. If your ADU concept includes a roof deck or a second-story balcony, factor in design review time and the Major Design Review fee ($846 per the FY26 fee schedule).

Is my Coronado lot within ½-mile walking distance of the Ferry Terminal?

Answer capsule: State law uses walking distance, not radius. A straight half-mile radius around the Coronado Ferry Terminal (1201 First Street) is a rough indicator only. The legal test under Public Resources Code §21155 is the network walking distance along publicly accessible pedestrian routes. Confirm your specific address with a walking-distance analysis (ArcGIS network service area, Google Maps walking directions, or our free property check) before assuming you qualify for the state-law height bonus.

Walking-distance routes within half a mile of the Coronado Ferry Terminal at 1201 First Street — the legal standard, not a straight-line radius.

Why walking distance matters

Coronado’s bridge, Naval Base, golf course, and parks all create breaks in the pedestrian network. A lot 2,400 linear feet away from the ferry terminal in a straight line might be 3,400 feet by foot — outside the ½-mile (2,640-foot) walking-distance threshold. Conversely, a lot a bit farther in straight-line distance might be inside the walking-distance threshold via a continuous sidewalk route.

The Coronado Village area immediately surrounding the ferry terminal (the streets around First, Orange, and B Avenues) is most likely to fall within the walking-distance limit. The Coronado Cays, Silver Strand homes south of the Hotel del Coronado, and parts of Coronado Shores are most likely outside it. The neighborhoods in between require an address-by-address check.

How to check your specific lot

1. Plug your address into Google Maps walking directions from 1201 First Street. If the walking distance returns less than 0.5 miles (or 0.50 mi), you likely qualify for the state-law height bonus.
2. Document the result. Take a screenshot. Bring it to your pre-application meeting.
3. Verify with planning staff before committing to a design that depends on the bonus height.

What setbacks and lot rules apply to Coronado ADUs?

Answer capsule: The key setback rule is four feet from side and rear property lines for many new detached ADUs, with no additional setback required for qualifying conversions of existing structures or same-location replacements. Lot coverage, floor-area ratio, open-space, and similar standards cannot be applied in a way that blocks the protected 800-sq-ft ADU path under Government Code §66321(b)(3).

Four-foot side and rear setbacks

For new detached ADUs and JADUs not contained within the primary dwelling, Coronado requires:

• Four feet from the side property line
• Four feet from the rear property line
• Front setback as required by the underlying zone, with the §66321(b)(3) override that allows an 800-sq-ft ADU in the front yard when no other location supports it

Zero setback for conversions and same-location replacements

A meaningful Coronado-specific rule: if you convert existing living area or an existing accessory structure into an ADU, no setback is required. The same applies to a new ADU built in the same location and dimensions as a legally approved existing structure. The zero-setback path is the cleanest legal route on a tight Coronado lot.

Beach Overlay Zone

Properties located between the ocean and the first public roadway in the Beach Overlay Zone must comply with street-yard setbacks intended to protect public ocean views. If your property sits in the Beach Overlay, factor in the additional view-protection setback standards.

Carriage houses: Coronado’s distinct conversion path

Coronado’s municipal code defines a “carriage house” as a two-story accessory building containing a garage on the first story and a habitable unit on the second story, detached from the main building. The city’s housing-element analysis identified roughly 117 existing carriage houses in Coronado at the start of the 6th-cycle planning period, and the ordinance permits their conversion to ADUs under CMC §86.56.105.D.

The carriage-house path is unique to Coronado among San Diego County cities. HCD flagged the layered-standards requirement as too restrictive in Finding 26: once converted, the structure is an ADU and should be permitted as an ADU, not under the full carriage-house standards.

How many ADUs can you build on a Coronado lot?

Answer capsule: Coronado’s local code says no more than one JADU or one ADU per single-family lot, with a state-law-protected combination exception under subsection (C)(2). Under Government Code §66323, an owner can also pair a state-protected ADU with a JADU on the same lot ministerially. On a multifamily lot with an existing multifamily dwelling, state law allows up to eight detached ADUs (capped at the number of existing units) plus interior conversion ADUs up to 25 percent of the existing unit count.

Single-family lot scenarios

Multifamily lot scenarios

State law as updated by SB 1211 (Statutes of 2024) and §66323 allows:

• Conversion ADUs within an existing multifamily building: up to 25 percent of existing unit count (rounded down), minimum of one.
• Detached ADUs on a lot with existing multifamily: up to eight, capped at the number of existing units on the lot. A four-unit building → 4 detached ADUs; an eight-unit building → 8.

Coronado’s local code still references “up to two detached ADUs” on multifamily lots — language HCD flagged as non-compliant.

What are the parking rules for Coronado ADUs?

Answer capsule: Coronado requires one off-street parking space per ADU under its Local Coastal Program and the Coastal Act of 1976; no additional parking is required for JADUs. State law independently allows several parking exceptions that Coronado’s ordinance doesn’t acknowledge, and bars replacement parking when a garage or carport is converted to an ADU under most general state-law conditions. Parking is the area where Coronado’s coastal carve-out most often meets state ADU law head-on.

Why Coronado can require parking when most California cities cannot

Most California cities cannot require parking for an ADU located within ½-mile walking distance of public transit, in a historic district, or where on-street parking permits are required but not offered to the ADU occupant. Coronado argues — and the Coastal Act of 1976 generally supports — that the entire city sits within the coastal zone, parking is essential to maintaining public coastal access, and the city’s certified Local Coastal Program may impose parking standards that the general state ADU exceptions otherwise eliminate.

The legal hook is Government Code §66329, which preserves the Coastal Act’s authority over coastal-access policy.

How does the coastal permit work for Coronado ADUs?

Answer capsule: Because Coronado has a certified Local Coastal Program (LCP, certified December 1983), most ADU permits are processed through the integrated coastal review, not a standalone Coastal Development Permit from the Coastal Commission. AB 462 (effective October 10, 2025) formalized concurrent processing: the two reviews run simultaneously, the combined decision is made within 60 days of a complete application, and the result is not appealable to the Coastal Commission for qualifying ADUs.

From Coronado’s Planning Fee Schedule effective July 1, 2025:

For most Coronado ADU projects, the concurrent coastal permit fee of $1,479 is the line item that applies. Verify the current fee at intake before submittal.

Does Coronado have pre-approved ADU plans?

Answer capsule: Per the City’s adopted Housing Element fact sheet, Coronado is developing a pre-approved ADU plan program that homeowners can use at no cost beyond standard permitting fees. As of our most recent verification, the pre-approved plans are described as in development, not as a published catalog. Verify current status with Coronado Community Development before factoring pre-approved plans into your timeline.

In other San Diego County cities — Encinitas, Chula Vista, San Marcos, El Cajon, and elsewhere — pre-approved ADU plans (sometimes called PAADU or PRADU) accelerate review by trading custom design for a faster permitting clock. State law (AB 1332, AB 434) requires cities to make pre-approved plans publicly available and to issue a permit on a pre-approved plan within 30 calendar days of a complete application.

How does the Coronado ADU permit process work?

Answer capsule: Coronado processes ADU applications ministerially under CMC §86.56.105. The city has 15 business days to determine completeness, and 60 days after a complete application is on file to approve or deny. Real-world permit timelines from public records range from same-day issuance to 412 days, with a median around 129 calendar days in the January 2025–April 2026 window.

The 7-step Coronado ADU permit process — from initial zoning check to certificate of occupancy.

What do real Coronado ADU permit timelines look like (2025–2026)?

Answer capsule: We reviewed public Coronado Building Services monthly issued-permit records from January 2025 through April 2026 and identified nine permits labeled as ADU or ADU/JADU. The applied-to-issued spans ranged from same-day issuance to 412 calendar days. The median across all nine records was 129 calendar days. Excluding the mixed-scope outlier, the median was 122 days. These are illustrative public-record observations, not guarantees of approval timing for new applications.

Source: City of Coronado Building Services monthly issued-permit PDFs, January 2025 through April 2026, pulled from coronado.ca.us.

What does a Coronado ADU permit actually cost?

Answer capsule: A typical Coronado ADU project pays planning fees, building permit fees, school fees, utility connection fees, and (where applicable) coastal-permit fees. Based on publicly issued permits from 2025 and 2026, total city permit fees on Coronado ADU records have ranged from about $1,300 to $9,700+, depending on project size and scope. ADUs 750 sq ft or smaller of interior livable space are exempt from impact fees under state law.

Planning fees that may apply

From the Coronado Planning Fee Schedule effective July 1, 2025:

School fees (Coronado Unified School District)

CUSD’s posted statutory school fee is $5.17 per square foot of assessable space for new residential construction. Under Government Code §66311.5 (as amended by SB 543, eff. Jan. 1, 2026), an ADU or JADU with less than 500 square feet of interior livable space does not increase assessable space and may avoid this fee. A 1,000-sq-ft detached ADU at $5.17/sq ft = $5,170 in school fees alone. Verify CUSD’s adopted rate at intake.

Impact fees (state-law exemption for smaller ADUs)

• ADUs with 750 sq ft or less of interior livable space: no impact fees from local agencies, special districts, or water corporations.
• JADUs with 500 sq ft or less of interior livable space: no impact fees.
• ADUs over 750 sq ft: impact fees are charged proportionately in relation to the square footage of the primary dwelling.

Putting it together

What does it actually cost to build an ADU in Coronado?

Answer capsule: Detached ADU construction in San Diego County turnkey runs $375–$600+ per square foot for vertical build, with most homeowners investing roughly $300,000–$450,000+ for a complete build including design, permits, sitework, and utilities, per SnapADU’s March 2026 market data. Coronado-specific projects tend to land at the higher end of that range. Garage conversions typically land at $150,000–$250,000.

Source basis: SnapADU’s March 2026 San Diego ADU cost data supports the $375–$600+/sq ft range. The California Construction Cost Index shows a 44 percent increase from January 2021 through December 2025, providing context for the 2026 cost levels. Coronado-specific premiums above the mainland San Diego benchmark are our editorial conclusion; verify with local builder bids.

Why Coronado costs run higher (editorial conclusion)

1. Bridge logistics. Material delivery, dumpster service, and contractor commute times all factor in.
2. Tight site access. Many Coronado lots are 50–75 feet wide with limited side-yard space; staging is harder than typical suburban San Diego.
3. Smaller local contractor pool. Fewer contractors carry deep familiarity with Coronado’s certified LCP and historic-overlay considerations.
4. Higher-end finish expectations. Coronado homes in the 92118 ZIP code average well into seven figures; ADU finishes that match the primary residence cost more.
5. In-person submittal friction. Designer and architect time spent on physical submittal trips adds to soft costs.

How do you finance a Coronado ADU?

Answer capsule: Most Coronado ADU projects are financed through cash-out refinance, home equity line of credit (HELOC), construction-to-permanent loans, or renovation refinance products. Coronado’s median home values (well into seven figures) typically give homeowners enough equity to fund $300,000–$500,000+ projects.

We present financing as paths, not ranked lenders. None of the following is “best” in the abstract — each fits different equity positions, project sizes, and timing needs.

The four financing paths most Coronado owners consider

Grants and special programs

CalHFA ADU Grant Program. Per CalHFA’s official ADU Grant page, the latest round of ADU funding has been fully allocated. Do not factor the grant into your budget unless CalHFA posts a new funding round.

San Diego Housing Commission ADU Finance Program. Per the SDHC ADU page, this is a currently active program offering construction-to-permanent loans up to $250,000 plus technical assistance to moderate-income homeowners — but eligibility is limited to residential property in the City of San Diego. Coronado homeowners are not eligible.

Do Coronado HOAs, historic districts, or the Coronado Cays restrict ADUs?

Answer capsule: California’s AB 670 (2019) prohibits HOAs from outright banning ADUs that comply with state law. AB 130 (Statutes of 2025) further bars HOAs from imposing fees or financial requirements tied to ADU development. HOAs may impose objective, reasonable design and aesthetic standards. The Coronado Cays HOA, the Coronado Shores Association, and Coronado’s historic-preservation rules each apply different layers of private or city-level review beyond the standard ADU permit.

Coronado Cays

The Coronado Cays community at the southern end of the Silver Strand operates under a Master Association with sub-association overlays for each village (Trinidad, Antigua, Mardi Gras, Bahama, and others). The Coronado Cays HOA member handbook documents specific ADU/JADU restrictions worth verifying before design: ADUs and JADUs (and garage conversions) are recorded as prohibited in the Cays’ condominium villages, and City-permitted ADUs/JADUs require prior written Association approval in other villages.

Treat this as a private-restriction issue to verify against the current handbook, your specific village, and counsel. State HOA law constrains what private associations can require — AB 670 and AB 130 prevent outright prohibition and tied financial requirements — but enforcement happens through civil disputes between the association and the homeowner, not at the city permit counter.

Coronado Shores

The Coronado Shores Association governs the high-rise condominium complex south of the Hotel del Coronado. ADUs are not generally feasible in high-rise condominium units, and the Association’s CC&Rs typically address remodeling rather than ADU construction.

Historic district considerations

Coronado’s historic preservation rules can apply to properties individually listed on the Coronado Historic Register, properties contributing to recognized historic districts, and carriage houses with documented historic significance. The Historic Resource Alteration Permit (HAP) fee is $140 (subsidized). HAP with Demolition is $4,030. If your property has a Mills Act agreement, additional compliance applies.

What can stop or delay a Coronado ADU?

Answer capsule: The biggest delays in Coronado ADU permitting are rarely outright denials. They are usually incomplete applications, design-review triggers, coastal documentation gaps, HOA/CC&R conflicts, building-code upgrades on conversions, utility-connection complications, and disputes over parking or rental term where state law and local code diverge.

1. Incomplete application. Missing Title 24 calcs, missing parking diagrams, unclear coastal documentation, or unresolved HOA referrals are the most common reasons a Coronado ADU application gets returned. Address all items on Handout 721 before submittal.
2. Path confusion. Applying for a “standard” ADU when a §66323 path provides more flexibility — or vice versa — adds review cycles.
3. Coastal documentation. Even with AB 462’s concurrent review, applicants who don’t submit complete coastal documentation up front face resubmittal cycles.
4. HOA conflict. Cays village restrictions, CC&R conflicts, and HOA-required pre-approvals can delay plans before you even reach the city counter.
5. Building-code upgrades. Converting an older detached garage often triggers electrical, plumbing, and insulation upgrades beyond simple ADU permitting.
6. Utility-connection complications. Separate meters, capacity upgrades, and SDG&E service-extension timelines can add weeks to months.
7. Parking and rental-term disputes. Owners who cite state law on replacement parking or the six-month rental minimum should come prepared with the HCD findings letter and the relevant statute.

Which Coronado ADU path is right for your situation?

Answer capsule: The fastest legal path is usually a conversion ADU (interior or garage conversion) or a JADU, because both qualify for state-protected ministerial approval with the cleanest setback rules. The right path depends on your goals, not on a generic ranking.

What should you do before paying for Coronado ADU plans?

Answer capsule: Before spending money on architectural plans, confirm your zoning, identify your legal ADU path, check HOA/CC&Rs, verify the controlling parking and rental rules for your situation, estimate fees and school fees, and ask the City the specific questions tied to your path.

A 7-step pre-design checklist:

1. Confirm property type, zone, and HOA status. Use the City’s Property Zoning Lookup, your CC&Rs, and a survey if you don’t already have one.
2. Pick the ADU type. Detached, attached, conversion, JADU, or carriage-house conversion — each has different rules and cost profiles.
3. Check the size, height, and setback path that applies. If you may be within ½-mile walking distance of the ferry terminal, run a walking-distance check and document the result for the height bonus.
4. Resolve parking and rental term up front. If a garage conversion is in scope, prepare your state-law reference. If you intend to do 31-day-or-longer rentals, ensure your covenant reflects current state law by category.
5. Check coastal, HOA, historic, and private restrictions. Each adds documentation, not necessarily denial.
6. Estimate fees and school fees. Use the city’s 2025 fee schedule plus CUSD’s $5.17/sq ft for new residential construction over 500 sq ft of interior livable space.
7. Decide your next step. Feasibility check first, then designer or builder consultation, then financing path discussion.

Coronado ADU laws — FAQ

How we researched this Coronado ADU guide

The Dwelling Index is an independent research resource covering ADU financing, costs, and regulations. We are not a builder, lender, broker, or city contractor.

To build this guide, we reviewed:

• Coronado Municipal Code §86.56.105 and §86.56.110 (ADUs, JADUs, and carriage houses), pulled directly from the city’s published code.
• California Government Code §§ 66310–66342 (state ADU law), with attention to SB 543, SB 9, AB 1154, and AB 462 (all Statutes of 2025, with effective dates in 2025 and 2026).
• California Department of Housing and Community Development findings letter to the City of Coronado dated December 10, 2025, identifying 31 separate findings of non-compliance with state ADU law. HCD’s ADU Ordinance Review Letters tracking spreadsheet records response-letter status for each reviewed jurisdiction, including Coronado.
• City of Coronado Planning Fee Schedule effective July 1, 2025, adopted by City Council Resolution 2025-10.
• City of Coronado Building Services monthly issued-permit PDFs from January 2025 through April 2026, for the public permit-timeline dataset (9 ADU-labeled records identified, including one mixed-scope outlier).
• Coronado Unified School District statutory school-fee notice ($5.17 per square foot of assessable space for new residential construction).
• City application materials: Handout 721 (ADU/JADU application), Handout 303 (building plan set requirements), Handout 723 (pre-application meeting).
• HCD ADU Handbook (2026 update, including the December 2025 addendum summarizing 2025 legislative changes).
• Construction cost data: SnapADU’s March 2026 San Diego market data ($375–$600+/sq ft, $300K–$450K+ complete-build), with the California Construction Cost Index (December 2025, 44 percent increase from January 2021) providing context.
• Coronado Cays HOA member handbook for the documented Cays-specific ADU/JADU restrictions.
• Voice-of-customer signals: Reddit, Houzz, Pacific Legal Foundation case documentation — used only to inform homeowner-language framing, never as proof for legal or cost claims.

We separated verified commercial facts (program availability, eligibility, fee schedules), regulatory facts (state and local code citations), and editorial conclusions (our analytical reading of the facts). Editorial conclusions are explicitly framed as such throughout this guide.

This page is general legal and zoning education, not legal advice. Verify your address-specific path with the City of Coronado Community Development Department (619-522-7326) or a qualified professional before relying on any of the rules described here.

Related Dwelling Index guides

• Coronado Coastal Zone ADU 2026: Rules, Fees & Timeline Guide — The companion guide focused on coastal permitting and CDP timing
• California ADU Laws 2026 — Statewide rules primer
• San Diego Coastal Zone ADU — Adjacent coastal-zone context for City of San Diego properties
• San Diego County Pre-Approved ADU Plans (2026) — Pre-approved plan options across the region
• How Much Does an ADU Cost? Real 2026 Prices by Type — National cost benchmarks
• ADU Financing Options — Cash-out refi, HELOC, construction-to-perm, and renovation refinance compared
• Detached ADU Floor Plans: 15 Layouts — Layout inspiration for studio through two-bedroom units